World : Tesla is changing the electric grid

There's a good chance flipping on the light switch 10 years from now will feel just as ordinary as it did for your parents and grandparents.

But behind the scenes, a radically different system for sending electrons where they're needed will be turning on those lights. Electrical power that today comes from massive centralized generation stations could originate from your neighbors' solar panels, then wait a few hours in a mammoth battery in your garage until you get home.

That's because the biggest change to our power grid since it was first built more than a century ago has begun. And this time we're all sharing the control once held by the companies that generate power and ones that distribute it.

Ordinary citizens, startups and decades-old power companies are all involved in the transformation. But one of the trend's biggest visionaries — and beneficiaries — is Tesla CEO Elon Musk. He'll sell you solar rooftop tiles to generate electricity, a giant battery to store all that energy and an electric car to suck it up.

Musk is a few steps ahead of the market. But he's helping to create a power grid where anyone can generate electricity as well as consume it, and where large batteries in the home — and even in utility companies — absorb electric power when there's plenty and pump it out when there's not enough.

Zero cushion

Most of us fuel up our cars before we run out of gas. But the electric grid works differently. Power and utility companies must exactly balance supply with what people consume at any given moment. UK grid operators famously must cope with a demand surge after the TV soap opera "EastEnders" ends, when thousands of people start boiling water for tea.

It's remarkable the power grid system works as reliably as it does. Here's a personal finance comparison: Many people keep a cushion of cash in their bank accounts to absorb daily financial fluctuations, but grid operators have to work with zero cushion.

Here's where the future gets tricky.

Coal, hydroelectric and nuclear power plants usually produce a steady supply of electricity. Others, like the increasingly common ones burning natural gas, are switched on to meet peak demands. But alternative energy sources, chiefly solar arrays and wind turbines, only work when the sun and wind cooperate. That makes it harder to match supply and demand, especially when people get home from work just as solar panels stop generating.